1. Field of the Invention
The present invention relates to an image recording apparatus for recording an image by adhering ink etc. to a record medium such as paper, film, etc., and more specifically to an image recording apparatus and a method for controlling the image recording apparatus for detecting a record error occurring when a recording process is performed on a record medium according to image record data.
2. Description of the Related Art
The ink jet system is one of the image recording systems used by an image recording apparatus such as a printer, a FAX, a copying machine, etc. An image recording apparatus in the ink jet system records an image by jetting ink drops from a plurality of nozzles provided in a recording head to a record medium held and conveyed by a conveying device, and can record a high quality image at a high speed.
The image recording apparatus in the ink jet system is widely used in office application such as recording images on a record medium in a cut sheet form. Recently, a number of recording heads have been arranged in an array orthogonal to the conveyance direction of a record medium, thereby improving the throughput, and have also begun to be used in industrial applications such as recording images on a continuous record medium such as roll paper or the like.
Some image recording apparatuses for recording images by adhering ink on a large number of record media record the images while conveying the record media at a high speed of tens through hundreds m/min.
There is the problem with the image recording apparatus in the ink jet system that a head nozzle which jets ink becomes blocked, thereby largely degrading the quality of recorded images. To overcome the problem, there is a configuration of detecting a record error by electronically reading a recorded image and comparing the image with an image represented by the image data transmitted from an upper device.
Especially when a record error is to be detected on the image recording apparatus which uses continuous paper (roll paper), a test pattern is recorded on a record medium after the conveying speed of the record medium reaches a specific speed, the recorded image is read, and a record error is checked. Therefore, a significant volume of wasteful record medium is conveyed until a roil of paper having a great deal of inertia reaches the specific conveying speed, thereby incurring the waste of resources and a high running cost.
In this situation, the apparatus disclosed by the Japanese Laid-open Patent Publication No. 2003-48309 (hereinafter referred to as the patent document 1, and incorporated herein by reference) defines a stepwise variable operation period applied before the target conveying speed of a record medium is reached. Then, a check and an adjustment are made in the variable operation period while the record medium is conveyed at an adjusted constant speed, and when the adjustment is completed, the conveying speed is increased by a specific increment α. Afterwards, an operation is performed at a constant speed for a specific number β of copies. By repeating the above-mentioned operation while increasing the operating speed up to a practical operating speed, an occurrence of wasteful record medium can be suppressed.